Disclosed is an apparatus for use in the delivery of an intravascular filter. Also disclosed is a method of using the disclosed apparatus in the delivery of an intravascular filter.
The intravascular filter is constructed and arranged for use in the circulatory system for capturing emboli. As used herein, the term “emboli” refers to something which travels through the bloodstream and which has a structural configuration and composition such that it could become lodged in a blood vessel and creates some degree of blockage to flow through the blood vessel. Examples of emboli include a detached blood clot or a larger piece of a blood clot, a clump of bacteria, stenosed material and more generically, something which could pose a risk of creating an obstruction. A pulmonary embolism occurs when a blood clot dislodges from the wall of a vein and migrates to the lung where it blocks blood flow in the pulmonary artery. Such clots are more likely in patients immobilized by disease, injury or following surgeries. Since a pulmonary embolism can cause severe patient injury or even death, there is a need for intravascular filters of the type described herein. More specifically, there is a need to have a safe and effective inferior vena cava (IVC) filter.
The design focus of an intravascular filter, such as an IVC filter, is on providing a structure which is capable of trapping these emboli so as to prevent them from reaching the heart and lungs. In order to have a safe and effective treatment, the design and construction of the intravascular filter is important as well as the design and construction of the delivery apparatus. The method of using the delivery apparatus for placement and positioning of the intravascular filter is also important.
The specific focus of the disclosed apparatus and method, as exemplified by the illustrated and described embodiments, is directed to the delivery of an intravascular filter into the inferior vena cava (IVC). The IVC is the large vein in the abdomen that returns blood from the lower body to the heart. As such, the IVC represents a preferred location for an intravascular filter to capture, trap and retain emboli, such as detached blood clots or larger pieces of blood clots which may develop in the veins of the leg or pelvis. Blood clots that develop in the veins of the leg or pelvis, a condition called deep vein thrombosis (DVT), occasionally break up and a larger piece of the clot can travel to the heart and lungs. The flow path to the heart and lungs includes passage through the IVC. This makes the IVC a suitable location for the placement and positioning of a capturing intravascular filter, such as the IVC filter which is disclosed herein.
The prior art includes IVC filters constructed and arranged as permanently installed devices. However, there can be long term risks associated with leaving the IVC filter in place. Therefore, more recently design efforts have been directed to the design and construction of IVC filters for temporary placement and subsequently retrieval and removal. The removal of the IVC filter from the patient may be performed when the risk of a traveling emboli, such as a detached blood clot (or a larger piece of a clot or other emboli) has passed. Once the risk of a traveling emboli reaching the heart and lungs has lessened, removal of the IVC filter can be considered.
As with any device or apparatus which is emplaced, implanted or in some fashion delivered into a patient, the ease of delivery is important. It is also important to be able to ensure the proper placement and positioning of the device. With certain devices, if the initial positioning of the device is not within the acceptable parameters, the device may have to be retrieved and removed and the procedure repeated. Therefore, the manner of guidance for the device, the reliability of the procedure and the repeatability of the procedure are important aspects. It is also important with any such device or apparatus which is to be removed from the patient at some point in time to have a design for that device which enables and facilitates retrieval and removal.
Another aspect of the delivery process is the manner in which it can be performed and the required environment for performing that procedure. The prior art procedure is currently performed under fluoroscopic guidance. A percutaneous delivery set and fluoroscopy suite are required to perform the prior art procedure. Further, transport of the patient to the fluoroscopy suite is required and this can be difficult and time consuming, especially for trauma patients. The procedure according to the present disclosure instead uses an intravascular ultrasound (IVUS) transducer for visual guidance. Importantly, the entire ultrasound procedure is able to be performed, according to the present disclosure, without removing the IVUS transducer until the IVC filter is essentially fully emplaced. The withdrawal of the IVUS transducer from the vein enables the clinician to verify the final positioning and emplacement of the IVC filter. This means that during dilation, sheath placement, filter delivery and placement verification are able to be performed by means of a safer procedure. As a further benefit, the clinician has higher confidence in the procedure because the clinician is able to “see” what is happening based on ultrasound imaging. The described IVUS procedure is able to be performed bedside which reduces cost and improves safety.